F.B.I. Opening Door to Wide Use Of Genetic Tests in Solving Crimes

Published: June 12, 1989

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The process is considered the biggest advance in forensics since the turn of the century, when Sir Edward Richard Henry figured how to use human fingerprints to identify criminals. The new process, however, has the potential to save considerable money by shortening police investigations and, by its precision, increasing conviction rates.

Fingerprints are unique to each individual, but within a person's DNA are the most intimate physical secrets including indicators of hereditary diseases likely to develop. Civil Libertarians Concerned

While a boon to law enforcement authorities and increasingly accepted by courts, the new technology has raised concerns among civil libertarians that such profiling may become routine or required for all or certain segments of society. Colorado, for instance, now requires DNA profiling of people convicted of sex offenses before they are released.

While the planned national computerized bank of DNA profiles could help track criminals, identify lost children or human remains and determine parentage, the same information bank could provide employers and insurance companies with valuable confidential information on prospective employees or customers.

DNA profiling is done by extracting the DNA from cells and cutting it into smaller pieces. Radioactive probes are added and they combine with certain repetitive sequences of the four nucleotides that are DNA's building blocks. Clues From Wad of Gum

When exposed to film over several days, the result is a pattern similar to grocery store bar codes. If sufficient probes are applied, a genetic pattern emerges that scientists say is unique to one person among many millions or even billions. This is most helpful in positively identifying sex offenders; in homicides DNA profiling usually can only place a suspect at the scene.

The F.B.I. now accepts specimens for DNA profiling only in violent personal crimes with a specific suspect, or serial rapes or child molestations without a suspect. To promote the technology's use, the agency is training 60 local technicians a year to help establish local DNA profiling labs, which can cost over $100,000. The agency does not charge police departments for the test, which it says cost about $30. The F.B.I is also holding an international conference on the process June 19-23 in Quantico, Va.

An additional procedure under research enables lab workers to take specimens with inadequate amounts of DNA and force a biological replication of the same material until enough DNA is produced to study patterns. Thus, a wad of gum, a cigarette butt, a sweat stain or even a few cells deposited on the back of a postage stamp from the saliva of a kidnapper mailing a ransom note would be sufficient to construct a person's unique DNA profile.

''There are five billion pairs of nucleotides in a person's DNA makeup,'' said Mr. Nimmich. ''Three pair determine the color of hair, three pair determine the color of eyes. It's just a matter of time until we find the right pairs to draw a physical profile of a person just from their DNA.''